• Korean Journal of Environment and Ecology
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• v.33 no.4
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• pp.378-401
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• 2019

This study generated a list of plants in eight sections from the Baekdansa ticket office (874m) to Cheonjedan (1,560m) divided in the interval of 100m above sea level to examine the species diversity patterns and distribution changes of the vascular plants at different altitudes in Taebaeksan National Park. Four site surveys found a total of 385 taxa: 89 families, 240 genera, 345 species, 5 subspecies, 34 varieties, and 1 form. A result of analyzing the change of species diversity along elevational gradients showed that it decreased with increasing elevation and then increased from a certain section. A result of analyzing habitat affinity types showed that the proportion of forest species increased with increasing elevation. On the other hand, the ruderal species appeared at a high rate in the artificial interference section. A result of comparing the proportion of woody and herb plants showed that the woody plants gradually increased with elevation and rapidly decreased in the artificial interference section. On the other hand, the herb plants showed the opposite trend. A result of analyzing the change of distribution of species according to altitude with the DCA technique showed that the vascular plants were divided into three groups according to the elevation in order on the I axis with the boundaries at 900m and 1,300m above sea level. The arrangement of each stand from right to left along the altitude on the I axis with a significant correlation with warmth index (WI) confirmed that the temperature change along the altitude could affect the distribution of vascular plants, composition, and diversity. Therefore, the continuous monitoring is necessary to confirm ecological and environmental characteristics of vegetation, distribution ranges, changes of habitat. We expect that the results of this study will be used as the basic data for establishing the measurement measures related to the preservation of biodiversity and climate change.

• Journal of Applied Biological Chemistry
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• v.62 no.3
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• pp.287-292
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• 2019

Pseudomonas tolaasii causes brown blotch disease on the oyster mushroom (Pleurotus ostreatus). Various pathogenic strains of P. tolaasii were isolated and divided into three subtypes, $P1{\alpha}$, $P1{\beta}$, and $P1{\gamma}$. For phage therapy, bacteriophages against to these subtype strains were applied to mushroom cultivation and very successful to prevent from the disease. In this study, bacteriophages were isolated against the representative strains of subtype pathogens and their polyclonal antibodies were synthesized to investigate structural relationship among capsid proteins of phages. Phage preparations over $10^{10}pfu/mL$ were injected to rabbit thigh muscle and polyclonal antibodies were obtained after three times of boost injection. Titers of the antibodies obtained were over $2{\times}10^7Ab/mL$ for the phage ${\phi}6264$, $1{\times}10^6Ab/mL$ for the phage ${\phi}HK2$, and $1{\times}10^7Ab/mL$ for the phage ${\phi}HK19$ and phage ${\phi}HK23$. High specific activities were observed between antibodies and the corresponding bacteriophages. Some cross-reactivities between the antibodies and non-corresponding bacteriophages were also measured. Antibody $Ab{\phi}6264$ inactivated all phages of $P1{\alpha}$ subtype and only phage ${\phi}HK16$ among $P1{\beta}$ subtype phages. Antibody $Ab{\phi}HK23$ of $P1{\gamma}$ subtype neutralized all phages of $P1{\beta}$ subtype as well as the phage ${\phi}HK23$, showing the widest phage-inactivation range. When the structural-similarity studies of phages were investigated by using phage antibodies, closeness obtained by phylogenetic analysis of 16S rRNA genes of pathogenic strains were quite different from that of polyclonal antibody-specific structural similarity of phage capsid proteins. In conclusion, there is weak correlation between the host strain specificity of bacteriophage and its capsid structural similarity measured by phage antibodies.

• Korean Journal of Environment and Ecology
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• v.33 no.4
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• pp.422-439
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• 2019

The rear edge population is considered to have low genetic diversity and high risk of extinction according to a highly isolated distribution. However, the rear edge population is observed to have persisted for an extended period despite the low genetic diversity. As such, it is necessary to understand the ecological process involved in the persistence of the population. Viola mirabilis L. in Korea is considered the rear edge population from the perspective of the worldwide distribution. We surveyed the distribution range of V. mirabilis, which shows the isolated distribution in the central area of Korea, to find out the factors of its persistence. Next, we investigated and accessed the vegetational pattern of habitats, soil environment, phenology, self-compatibility, population structure, and extinction risk factors observed in the distribution area. V. mirabilis was distributed in the understory of the deciduous forest, planted forest of the deciduous conifer and deciduous broad-leaved trees, shrubland, and grassland in the limestone area. We also observed the re-establishment of seedlings in the population, and most of them showed a stable population structure. For chasmogamous flowers, the visit by pollinators has a significantly positive relationship with the production of fruits. However, we found that the production of the cleistogamous flowers was more numerous in all studied populations and that only the cleistogamous flowers were produced despite a more substantial plant size in some populations. The plant size was more related to the production of the cleistogamous flowers than that of the chasmogamous flowers. Accordingly, the cleistogamous flowers significantly contributed to seedling recruitment in the population. We found that the production of the chasmogamous flowers and the cleistogamous flowers did not have a correlation with the factors of the soil analysis except for phosphoric acid. V. mirabilis showed the self-incompatibility characteristics most likely due to the production capability of the cleistogamous flowers. Potential extinction risk factors observed in the distribution area was included the development of limestone mine, the expansion of agricultural fields, and the construction of houses. Although V. mirabilis showed an isolated distribution in the limestone area in the Korean peninsula, it showed a diverse distribution in a wide habitat environment ranging from the grassland to the understory of the trees with relatively low canopy closure rate. Moreover, we concluded that the persistence of the population was possible if we can maintain the current state of multiple populations and stable population structure.

• Korean Journal of Agricultural and Forest Meteorology
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• v.21 no.1
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• pp.29-41
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• 2019

Terrestrial Gross Primary Production (GPP) is the largest global carbon flux, and forest ecosystems are important because of the ability to store much more significant amounts of carbon than other terrestrial ecosystems. There have been several attempts to estimate GPP using mechanism-based models. However, mechanism-based models including biological, chemical, and physical processes are limited due to a lack of flexibility in predicting non-stationary ecological processes, which are caused by a local and global change. Instead mechanism-free methods are strongly recommended to estimate nonlinear dynamics that occur in nature like GPP. Therefore, we used the mechanism-free machine learning techniques to estimate the daily GPP. In this study, support vector machine (SVM), random forest (RF) and artificial neural network (ANN) were used and compared with the traditional multiple linear regression model (LM). MODIS products and meteorological parameters from eddy covariance data were employed to train the machine learning and LM models from 2006 to 2013. GPP prediction models were compared with daily GPP from eddy covariance measurement in a deciduous forest in South Korea in 2014 and 2015. Statistical analysis including correlation coefficient (R), root mean square error (RMSE) and mean squared error (MSE) were used to evaluate the performance of models. In general, the models from machine-learning algorithms (R = 0.85 - 0.93, MSE = 1.00 - 2.05, p < 0.001) showed better performance than linear regression model (R = 0.82 - 0.92, MSE = 1.24 - 2.45, p < 0.001). These results provide insight into high predictability and the possibility of expansion through the use of the mechanism-free machine-learning models and remote sensing for predicting non-stationary ecological processes such as seasonal GPP.

• Korean Journal of Remote Sensing
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• v.35 no.2
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• pp.251-263
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• 2019

Sentinel-2 Multi Spectral Instrument(MSI) launched by the European Space Agency (ESA) offered high spatial resolution optical products, enhanced temporal revisit of five days, and 13 spectral bands in the visible, near infrared and shortwave infrared wavelengths similar to Landsat mission. Landsat satellite imagery has been applied to various previous studies, but Sentinel-2 optical satellite imagery has not been widely used. Currently, for global coverage, Sentinel-2 products are systematically processed and distributed to Level-1C (L1C) products which contain the Top-of-Atmosphere (TOA) reflectance. Furthermore, ESA plans a systematic global production of Level-2A(L2A) product including the atmospheric corrected Bottom-of-Atmosphere (BOA) reflectance considered the aerosol optical thickness and the water vapor content. Therefore, the Sentinel-2 L2A products are expected to enhance the reliability of image quality for overall coverage in the Sentinel-2 mission with enhanced spatial,spectral, and temporal resolution. The purpose of this work is a quantitative comparison Sentinel-2 L2A products and fully simulated image to evaluate the applicability of the Sentinel-2 dataset in cultivated land growing various kinds of crops in Korea. Reference image of Sentinel-2 L2A data was simulated by airborne hyperspectral data acquired from AISA Fenix sensor. The simulation imagery was compared with the reflectance of L1C TOA and that of L2A BOA data. The result of quantitative comparison shows that, for the atmospherically corrected L2A reflectance, the decrease in RMSE and the increase in correlation coefficient were found at the visible band and vegetation indices to be significant.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.2
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• pp.120-129
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• 2021

Securing a range of wheat resources is of particular importance with respect to wheat breeding, as it provides a broad genetic foundation. Although wheat breeders have used different wheat germplasms as material resources in current breeding systems, the traits of most germplasms collected from foreign countries differ from the unique traits that have evolved in the Korean environment. In this study, conducted over a 2-year period (2018 and 2019), we therefore evaluated the agricultural traits 1,967 wheat germplasms collected not only in Korea but also worldwide. During the period from sowing to February, the average temperature in 2019 was greater than 1℃, whereas from March to June, the average temperature was approximately 0.9℃ higher in 2018. Compared with the growth recorded in 2018, the stem length in 2019 increased by approximately 20 cm in 2019, and there were notable differences heading date and maturation between 2018 and 2019. In 2019, the heading dates of 973 and 713 wheat resources were earlier and later than those in 2018, respectively. Moreover, stem length was found to be highly correlated with the heading date and maturation. In Korea, where the rainy season and tine of rice transplantation overlap with the time of wheat harvest, early flowering time with high grain yield has been the most important selection target with respect to wheat breeding. We anticipate that the findings of this study will provide would use a foundation for the selection of elite materials and the development of resource core-sets for Korean wheat breeding programs.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.258-267
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• 2020

The agrivoltaic can produce electricity and grow crops on fields at the same time. It is necessary to analyze the cultivation environment and evaluate the crop productivity under agrivoltaic because the shading point changes according to structure of agrivoltaic and sun's position. Two types of "fixing" and "tracing" agrivoltaic were installed, and a rice cultivation experiment was conducted in the fields under each agrivoltaic and without shading (control). "Hyunpoombyeo" was transplanted on June 7, 2019, and grown with fertilization of 9.0-4.5-5.7 kg/10a (N-P-K). Fifteen weather stations were installed under each agrivoltaic to measure solar radiation and temperature, and yield and yield-related elements were investigated by points. The accumulated solar radiation during the rice growing season in fixing was no much difference between points, and that in tracing was much difference between points. However, the average solar radiations of two agrivoltaics were similar. The mean temperature, yield, and yield-related elements showed a significant difference for the shading rate, and decreased with increasing the shading rate except ripening grain rate and 1000 grain weight of fixing agrivoltaic. In the relationship between shading rate and yield, fixing and tracing were fitted to a logistic equation and a simple linear equation, respectively, and showed a high correlation (tracing: R2 = 0.62, fixing: R2 = 0.73). The shading rate variation by point for two types was large despite similar yield variation. Thus, it needs to be more closely examined the relationship of the shading rate for a specific period rather than the shading rate during the whole growing season.

• Journal of agriculture & life science
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• v.51 no.6
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• pp.89-105
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• 2017

This study utilized 32,312 records of 17 linear type and 10 conformation traits(including final scores) of Hanwoo cows in the KAIA(Korea Animal Improvement Association) ('09~'10), with 60,556 animals in the pedigree file. Traits included stature, body length, strength, body depth, angularity, shank thickness, rump angle, rump length, pin bone width, thigh thickness, udder volume, teat length, teat placement, foot angle, hock angle, rear leg back view, body balance, breed characteristic, head development, forequarter quality, back line, rump, thigh development, udder development, leg line, and final score. Genetic and residual(co) variances were estimated using bi-trait pairwise analyses with EM-REML algorithm. Herd-year-classifier, year at classification, and calving stage were considered as fixed effects with classification months as a covariate. The heritability estimates ranged from 0.03(teat placement) to 0.42(body length). Rump length had the highest positive genetic correlation with pin bone width(0.96). Moreover, stature, body length, strength, and body depth had the highest positive genetic correlations with rump length, pin bone width, and thigh thickness(0.81-0.94). Stature, body length, strength, body depth, rump length, pin bone width, and thigh thickness traits also had high positive genetic correlations.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.4
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• pp.19-24
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• 2020

In this work, the electrical property of Si-doped β-Ga2O3 was investigated via a post-growth annealing process. The Ga2O3 samples were annealed under air (O-rich) or N2 (O-deficient) ambient at 800~1,200℃ for 30 mins. There was no correlation between the crystalline quality and the electrical conductivity of the films within the experimental conditions explored in this work. However, it was observed the air ambient led to severe degradation of the film's electrical conductivity while N2-annealed samples exhibited improvement in both the carrier concentration and Hall mobility measured at room temperature. Interestingly, the x-ray photoemission spectroscopy (XPS) revealed that both annealing conditions resulted in higher concentration of oxygen vacancy (VO). Although it was a slight increase for the air-annealed sample, high resistivity of the film strongly suggests that VO cannot be a shallow donor in β-Ga2O3. Therefore, the enhancement of the electrical conductivity of N2-annealed samples must be originated from something other than VO. One possibility is the activation of Si. The XPS analysis of N2-annealed samples showed increasing relative peak area of Si 2p associated with SiOx with increasing annealing temperature from 800 to 1,200℃. However, it was unclear whether or not this SiOx was responsible for the improvement as the electrical conductivity quickly degraded above 1,000℃ even under N2 ambient. Furthermore, XPS suggested the concentration of Si actually increased near the surface as opposed to the shift of the binding energy of Si from its initial chemical state to SiOx state. This study illustrates the electrical changes induced by a post-growth thermal annealing process can be utilized to probe the chemical and electrical states of vacancies and dopants for better understanding of the electrical property of Si-doped β-Ga2O3.

• Journal of Bio-Environment Control
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• v.30 no.1
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• pp.1-9
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• 2021

This study was conducted to examine the changes of photosynthesis, growth, chlorophyll contents and functional material contents in light intensity and EC concentration of wild baby leaf vegetable, Indian lettuce (Lactuca indica L. cv. 'Sunhyang') in DFT hydroponics. The cultivation environment was 25±1℃ of temperature and 60±5% of relative humidity in growth system. At 14 days after sowing, combination effect of light intensity (Photosynthetic Photon Flux Density (PPFD 100, 250, 500 µmol·m-2·s-1) and EC level (EC 0.8, 1.4, 2.0 dS·m-1) of nutrient solution was determined at the baby leaf stage. The photosynthesis rate, stomatal conductance, transpiration rate and water use efficiency of Indian lettuce increased as the light intensity increased. The photosynthesis rate and water use efficiency were highest in PPFD 500-EC 1.4 and PPFD 500-EC 2.0 treatment. The chlorophyll content decreased as the light intensity increased, but chlorophyll a/b ratio increased. Leaf water content and specific leaf area decreased as light intensity increased and a negative correlation (p < 0.001) was recognized. Plant height was the longest in PPFD 100-EC 0.8 and leaf number, fresh weight and dry weight were the highest in PPFD 500-EC 2.0. Anthocyanin and total phenolic compounds were the highest in PPFD 500-EC 1.4 and 2.0 treatment, and antioxidant scavenging ability (DPPH) was high in PPFD 250 and 500 treatments. Considering the growth and functional material contents, the proper light intensity and EC level for hydroponic cultivation of Indian lettuce is PPFD 500-EC 2.0, and PPFD 100 and 250, which are low light conditions, EC 0.8 is suitable for growth.